As is known, pressure surges occur in pipelines when the flowing liquid is shut off. The size of the pressure surge depends herein on the speed with which shutoff takes place. In the older sanitary installations (domestic installations), only minor pressure surges occurred because the usual water faucets (globe valves) could be turned off only gradually. In the quick shutoff elements, especially lever mixers, utilized in more recent installations, however, throughflow can be interrupted abruptly so that a very strong water hammer is encountered. Investigations performed within the framework of this invention revealed that pressure rises of above 20 bar can be produced upon the rapid closing of lever mixers. With such high pressure surges, there is the danger of damage to the installation, especially to the fittings and the joints of plastic pipes.